There is plentiful prior art for methods and apparatus that attach stretched elastic ribbons at predetermined intervals to a relatively inelastic web material that is subsequently cut into discreet articles. The elastic ribbon is applied in the direction of web movement and hence the elastic functions to gather intermediate portions of the article, for example, portions of a disposable diaper that are adjacent to an infant's legs.
This field of prior art also includes methods and apparatus for applying discreet segments (instead of ribbons) of elastic to predetermined portions of a moving web for subsequent cutoff, again with the same function, but without the non-stretched excess elastic ribbon that extends beyond the predetermined bonded region.
Typical of the first approach involving a continuous ribbon are U.S. Pat. Nos. 4,081,301; 4,240,866; and 4,239,578. Other teachings relating to the application of discreet segments of stretched elastic to a moving web include U.S. Pat. Nos. 4,379,016 and 4,397,704.
The problem of applying a stretched continuous (or segmented piece) of elastic in a transverse direction to a moving web becomes much more complicated. One approach is suggested in U.S. Pat. Nos. 4,240,866 and 4,285,747 whereby an elongated web substrate is "gathered" at one or more locations in a direction transverse to web movement and, while the web is looped or gathered, applying nonstretched elastic ribbon on adjacent and outward marginal edges with the elastic bridging the transverse loop. At a point downstream, the gathered loop in the narrowed web is removed by stretching the web in a transverse direction, and when the connected series of articles are severed and put to use, the stretched elastic in the non-gathered article acts to cause selective transverse gathering. Another method and apparatus for applying elastic bands transversely to a moving web is shown in U.S. Pat. No. 4,284,454 albeit differences of function and use.
In the prior art method and apparatus of '454, parallel elastic ribbons are fed, cut off, and transported at right angles prior to adhesive placement and attachment to the continuously moving web. However, the right angle transposition involves transfer of the stretched elastic segments from one set of grippers to a second set of grippers, and also involves indexing movement of the conveyor having the first gripping means.